Results 11 to 20 of about 26,307 (200)

PAWS and POCO: NIR Astrophotonic Instruments for Astronomy

Astronomische Nachrichten, Volume 344, Issue 8-9, October-November 2023., 2023
Abstract For near‐infrared ground and space‐based astronomy, compact photonic devices can replace the large bulk optical components in spectrographs, frequency combs, beam combiners, and sky subtraction filters, thus saving cost, reducing volume, weight, and power requirements.
Kalaga Madhav, Alan Günther, Eloy Hernandez, Stella Vjes̆nica, Daniel Bodenmüller, Andreas Stoll, Christer Sandin, Haydar Altuğ Yıldırım, Martin M. Roth   +8 more
wiley   +1 more source

Detector system challenges of the wide‐field spectroscopic survey telescope (WST)

Astronomische Nachrichten, Volume 344, Issue 8-9, October-November 2023., 2023
Abstract The wide‐field spectroscopic survey telescope (WST) is proposed to become the next large optical/near infrared facility for the European southern observatory (ESO) once the extremely large telescope (ELT) has become operational. While the latter is optimized for unprecedented sensitivity and adaptive‐optics assisted image quality over a small ...
Roland Bacon, Martin M. Roth, Paola Amico, Eloy Hernandez, The WST Consortium   +4 more
wiley   +1 more source

Statistical Detection of the He ii Transverse Proximity Effect: Evidence for Sustained Quasar Activity for >25 Million Years

Frontiers in Astronomy and Space Sciences, 2017
The reionization of helium at z ~ 3 is the final phase transition of the intergalactic medium and supposed to be driven purely by quasars. The He ii transverse proximity effect—enhanced He ii transmission in a background sightline caused by the ionizing ...
Tobias M. Schmidt, Tobias M. Schmidt, Gabor Worseck, Joseph F. Hennawi, Joseph F. Hennawi, J. Xavier Prochaska, Neil H. M. Crighton, Zarija Lukić, Jose Oñorbe   +8 more
doaj   +1 more source

Emission of Energetic Neutral Atoms From the Magnetosphere‐Atmosphere Interactions at Callisto and Europa

Journal of Geophysical Research: Space Physics, Volume 128, Issue 10, October 2023., 2023
Abstract We analyze the emission of energetic neutral atom (ENA) flux from charge exchange between Jovian magnetospheric ions and the atmospheres of Callisto and Europa. For this purpose, we combine the draped electromagnetic fields from a hybrid plasma model with a particle tracing tool for the energetic ions.
C. Michael Haynes, Tyler Tippens, Peter Addison, Lucas Liuzzo, Andrew R. Poppe, Sven Simon   +5 more
wiley   +1 more source

Patchy Kinetic Sunyaev–Zel’dovich Effect with Controlled Reionization History and Morphology

The Astrophysical Journal, 2023
Using the novel semi-numerical code for reionization AMBER, we model the patchy kinetic Sunyaev–Zel’dovich (kSZ) effect by directly specifying the reionization history with the redshift midpoint z _mid , duration Δ _z , and asymmetry A _z .
Nianyi Chen, Hy Trac, Suvodip Mukherjee, Renyue Cen   +3 more
doaj   +1 more source

Inhomogeneous Reionization Models in Cosmological Hydrodynamical Simulations [PDF]

, 2019
In this work we present a new hybrid method to simulate the thermal effects of the reionization in cosmological hydrodynamical simulations. The method improves upon the standard approach used in simulations of the intergalactic medium (IGM) and galaxy ...
Davies, F. B., Hennawi, J. F., Lukić, Z., Oñorbe, Jose, Sorini, D.   +4 more
core   +2 more sources

Polarity Asymmetries in Rocket‐Triggered Lightning

Geophysical Research Letters, Volume 50, Issue 17, 16 September 2023., 2023
Abstract The dissonant development of positive and negative lightning leaders is a central question in atmospheric electricity. It is also the likely root cause of other reported asymmetries between positive and negative lightning flashes, including the ones regarding: stroke multiplicity, recoil activity, leader velocities, and emission of energetic ...
C. L. da Silva, W. P. Winn, M. C. Taylor, G. D. Aulich, S. J. Hunyady, K. B. Eack, H. E. Edens, R. G. Sonnenfeld, P. R. Krehbiel, E. M. Eastvedt, J. J. Trueblood   +10 more
wiley   +1 more source

CMB Neutrino Mass Bounds and Reionization [PDF]

, 2010
Current cosmic microwave background (CMB) bounds on the sum of the neutrino masses assume a sudden reionization scenario described by a single parameter that determines the onset of reionization.
Alessandro Melchiorri, Asantha Cooray, Maria Archidiacono, Stefania Pandolfi, Y. B. Zel’dovich   +4 more
core   +2 more sources

Cosmological Parameters from Planck Data in SU(2)CMB, Their Local ΛCDM Values, and the Modified Photon Boltzmann Equation

Annalen der Physik, Volume 535, Issue 7, July 2023., 2023
Implications for the cosmological model are explored of the assumption that the cosmic microwave background is subject to an SU(2) Yang– Mills theory of scale 10−4 eV rather than U(1) quantum thermodynamics. This concerns zeroth‐order (changes at high redshifts) and first‐order cosmological perturbations (changes at high and low redshifts).
Ralf Hofmann, Janning Meinert, Shyam Sunder Balaji   +2 more
wiley   +1 more source

Perspectives for Cosmological Reionization From Future CMB and Radio Projects

Frontiers in Astronomy and Space Sciences, 2018
In spite of the great recent results from the Planck satellite supporting cosmological reionization scenarios almost compatible with astrophysical models for the evolution of structure, galaxy and star formation, the full understanding of the ...
Tiziana Trombetti, Tiziana Trombetti, Carlo Burigana, Carlo Burigana, Carlo Burigana   +4 more
doaj   +1 more source